49. Separation provision during system degradation

Question 1

According to MATS 1, when may a controller use SSR alone or provide horizontal separation?

Answer 1

Provided the pilots are made aware of the limitations of the service, SSR may be used to provide horizontal separation in the following circumstances:

1) in accordance with MATS Part 2;
2) or overcome temporary deficiencies within PSR cover, such as fading or clutter, the SSR return only of one aircraft may be used to provide separation from the PSR or SSR return of another aircraft provided the PSR and SSR situation displays are correctly aligned. In this context, “unavailable for use due to maintenance” does not constitute a “temporary deficiency”;
3) immediately after PSR failure for the minimum time necessary to establish procedural separation. Once established, services normally provided using radar may be resumed when the PSR is serviceable.

Question 2

According to MATS 1, when shall a controller NOT use SSR alone to provide horizontal separation?

Answer 2

SSR shall not be used to provide horizontal separation if a controller has any doubt about the accuracy of the position symbol due to equipment malfunction, reflections or any other reason.